package com.zhouxiaoge.wc;

import org.apache.flink.api.common.typeinfo.Types;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.operators.AggregateOperator;
import org.apache.flink.api.java.operators.DataSource;
import org.apache.flink.api.java.operators.FlatMapOperator;
import org.apache.flink.api.java.operators.UnsortedGrouping;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.util.Collector;

/**
 * @author 周小哥 gqzmy@163.com
 */
public class BatchWordCount {
    public static void main(String[] args) throws Exception {
        // 1、创建执行环境
        ExecutionEnvironment environment = ExecutionEnvironment.getExecutionEnvironment();
        // 2、从文件读取数据
        DataSource<String> lineDateSource = environment.readTextFile("input/words.txt");
        // 3、将每行数据进行分词，转换成二元组
        FlatMapOperator<String, Tuple2<String, Long>> wordAndOneTuple = lineDateSource
                .flatMap((String value, Collector<Tuple2<String, Long>> out) -> {
                    String[] words = value.split(" ");
                    for (String word : words) {
                        out.collect(Tuple2.of(word, 1L));
                    }
                }).returns(Types.TUPLE(Types.STRING, Types.LONG));
        // 4、按照word进行分组
        UnsortedGrouping<Tuple2<String, Long>> wordAndOneGroup = wordAndOneTuple.groupBy(0);
        // 5、分组内进行聚合统计
        AggregateOperator<Tuple2<String, Long>> sum = wordAndOneGroup.sum(1);
        // 6、打印结果
        sum.print();

    }
}
